Insulated units, such as walk-in coolers or freezers, are typically box-like structures of sufficient size to allow an individual to walk around in the unit while standing up. The insulated unit, hereafter referred to as a “walk-in,” may be provided with a refrigeration system, or perhaps in certain applications a heating system, and is used for storing items at either low or high temperatures relative to the outside environment. For example, a walk-in may be used in grocery stores, convenience stores, bars or restaurants to store food products such as meat, cheese, beer, and a variety of other foods that are not immediately needed. Application may also be found in other industries, such as pharmaceutical laboratories.
To maximize the use of storage space within the walk-in, interior shelving is typically provided. This shelving may be free-standing or cantilevered. Examples of free-standing shelving are described in U.S. Pat. No. 3,424,111 to Maslow; U.S. Pat. No. 3,874,511 to Maslow; U.S. Pat. No. 4,811,670 to Kolvites; et al. and U.S. Pat. No. 6,017,009 to Swartz, et al.
However, cantilevered shelving, such as that shown in U.S. Pat. No. 5,645,257 to Ward, has the advantage of not having front vertical support posts that can hamper access to items on the shelves. Nevertheless, there are significant problems encountered in mounting cantilevered shelves in a walk-in. For example, because of the manner in which walk-ins are constructed, prior art systems that are strong enough to support shelving and the items on them tend to compromise the insulating properties of the walk-ins.
For purposes of explanation, the construction of a conventional walk-in cooler is described below with reference to the accompanying drawings.
As shown in the perspective view of FIG. 9, the walk-in 300 is typically constructed of a plurality of interlocking wall panels 100 and ceiling panels 200.
As shown in the partial plan and partial elevational views, which are respectively FIGS. 7 and 8, a conventional wall panel 100 comprises a core 102 of insulation, preferably polyurethane foam. An inner skin 104 and an outer skin 106, also called inner and outer sidewalls, are disposed on opposite sides of the core 102 and are preferably made of thin sheetmetal. The side edges 108, 110 of the wall panels are preferably not covered by sheetmetal except for a small marginal lip 107 formed where the sheetmetal skins 104, 106 have been folded inwardly at right angles. An elastomeric seal 109, made for example of rubber or plastic, is preferably provided on each lip 107 at adjoining edges of the panels to provide a seal between panels when they are assembled as described below. This seal minimizes migration of moisture through the walk-in and into the insulating core. In addition, the edges 108, 110 are preferably contoured so that one wall panel 100 can easily mate with an adjacent wall panel 101. A male-female C- or U-shaped contour is illustrated in FIG. 7, but a variety of contours, and even a straight profile, are possible.
Ceiling panels 200 are formed from the same components as the wall panels 100. As shown in FIG. 9, however, the assembly of the ceiling panels 200 differs in that the inner skin 204 does not extend all of the way to the side edges 208. Rather, the core 202 is exposed in a region near each edge 208. In this way, the ceiling panel 200 can mate with a top edge 110a of each wall panel 100 as shown in FIG. 9.
As will be appreciated, each wall panel 100 is formed to include one edge 108 having a female contour and one edge 110 having a male contour. In addition, each panel has an interlocking mechanism on the side of the male-contoured edge 110 to be secured at the female contour of an adjacent panel. The same principle of interchangeability also applies to ceiling panels 200. Of course, one of ordinary skill will understand that some panels, such as panels that make up corners or the front and back panels of the ceiling, will differ slightly from the wall and ceiling panels 100, 200 described above.
To form a wall, one wall panel 100 is interlocked with another wall panel 101 so that their edges 108, 110 mate, forming a joint. The wall panels house a plurality of interlocking mechanisms at a number of locations 116 along each edge 108, 110, as shown in FIG. 9. The interlocking mechanism typically comprises a suitable pawl 112 and cam-tightening means (not shown) in one panel and a catch (not shown) in the mating panel. The catch is preferably a metal rod embedded in any suitable fashion in the core 102. The pawl 112 engages the catch and interlocks the wall panels 100, 101 when a user rotates the cam-tightening means by way of a removable allen wrench 114. The ceiling panels 200 are interlocked together and are interlocked with the side panels in substantially the same manner.
In order to construct cantilevered shelving without compromising the insulating properties of the walk-in, a fastener would ideally engage only the inner skin 104 of a wall panel 100. However, the inner skin 104, being thin sheetmetal, is incapable of supporting substantial load applied by the shelving and the items placed on it. If the shelving is attached to the sheetmetal with such a fastener, when the shelving is loaded the sheetmetal may bend or the fastener may pull through it. As a result, conventional cantilevered shelving is normally attached to the walls with long bolts that pass through the inner skin 104, the core 102 and the outer skin 106. On the outside of the walk-in 300, a stress plate is generally used at each bolt to distribute the load over a large area to prevent pull-through. These bolts, however, serve as paths for heat transfer and can also allow humidity to enter into the walk-in, thus reducing its insulating properties.
Accordingly, there is a need in the art for a support that is strong enough to support loaded shelving, but which does not compromise the insulating properties of the walk-in.